Had my pool water tested by our local pool store, along side a couple strip tests because I suspected the PH level shown by my TF100 kit was off (I'm adding a lot of Alkalinity increaser each week).
TF100 (K1000) shows around 7.3, the store and strips measured 6.8 consistently (3 measurements each). There must be something else going on that I don't understand - could have a lot to do with TA being too low all the time (50-60). The TF100 kit is new. Pool temps cycle from 85 to 90F each day.
I ordered a self-calibrating PH tester (HI 98127) along with a 7.01 calibration solution for my Chemlink PH probe in the hope that I can have a strong frame of reference when I need it.